Microglia are brain-resident myeloid cells that mediate key functions to support the CNS. Microglia express a wide range of receptors that act as molecular sensors, which recognize exogenous or endogenous CNS insults and initiate an immune response. In addition to their classical immune cell function, microglia act as guardians of the brain by promoting phagocytic clearance and providing trophic support to ensure tissue repair and maintain cerebral homeostasis. Conditions associated with loss of homeostasis or tissue changes induce several dynamic microglial processes, including changes of cellular morphology, surface phenotype, secretory mediators, and proliferative responses (referred to as an “activated state”). Activated microglia represent a common pathological feature of several neurodegenerative diseases, including Alzheimer’s disease (AD). Cumulative evidence suggests that microglial inflammatory activity in AD is increased while microglial-mediated clearance mechanisms are compromised. Microglia are perpetually engaged in a mutual interaction with the surrounding environment in CNS; thus, diverse microglial reactions at different disease stages may open new avenues for therapeutic intervention and modification of inflammatory activities. In this Review, the role of microglia in the pathogenesis of AD and the modulation of microglia activity as a therapeutic modality will be discussed.

小胶质细胞是驻留在大脑中的髓样细胞，介导关键功能以支持中枢神经系统。小胶质细胞表达广泛的受体，它们充当分子传感器，识别外源或内源的中枢神经系统损伤并启动免疫反应。除了具有经典的免疫细胞功能外，小胶质细胞还可以通过促进吞噬作用清除并提供营养支持来确保组织修复和维持脑稳态，从而起到保护大脑的作用。与动态平衡丧失或组织改变相关的疾病会诱发几种动态的小胶质细胞过程，包括细胞形态，表面表型，分泌介质和增殖反应的改变（称为“激活状态”）。活化的小胶质细胞代表了几种神经退行性疾病的常见病理特征，包括阿尔茨海默氏病（AD）。累积证据表明，AD中的小胶质细胞炎症活性增加，而小胶质细胞介导的清除机制受到损害。小胶质细胞一直与中枢神经系统周围的环境互动。因此，在不同疾病阶段的各种小胶质细胞反应可能为治疗干预和改变炎症活性开辟新途径。在这篇综述中，将讨论小胶质细胞在AD发病机理中的作用以及作为治疗手段的小胶质细胞活性的调节。在不同疾病阶段的各种小胶质细胞反应可能为治疗干预和改变炎症活性开辟新途径。在这篇综述中，将讨论小胶质细胞在AD发病机理中的作用以及作为治疗手段的小胶质细胞活性的调节。在不同疾病阶段的各种小胶质细胞反应可能为治疗干预和改变炎症活性开辟新途径。在这篇综述中，将讨论小胶质细胞在AD发病机理中的作用以及作为治疗手段的小胶质细胞活性的调节。